Coating compositions for use with an overcoated photoresist

ABSTRACT

In a first aspect, organic coating compositions are provided, particularly spin-on antireflective coating compositions, that contain a polyester resin component. In a further aspect, coating compositions are provided that contain a resin component obtained by polymerization of a multi-hydroxy compound. Coating compositions of the invention are particularly useful employed in combination with an overcoated photoresist layer to manufacture integrated circuits.

The present application is a divisional of U.S. application Ser. No.10/256,225, filed Sep. 26, 2002, now U.S. Pat. No. 6,852,421, whichclaims the benefit of U.S. provisional patent application No.60/325,254, filed Sep. 26, 2001, which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to compositions (particularlyantireflective coating compositions or “ARCs”) that can reducereflection of exposing radiation from a substrate back into anovercoated photoresist layer and/or function as a planarizing orvia-fill layer. More particularly, the invention relates to organiccoating compositions, particularly antireflective coating compositions,that contain a polyester resin component.

2. Background

Photoresists are photosensitive films used for the transfer of images toa substrate. A coating layer of a photoresist is formed on a substrateand the photoresist layer is then exposed through a photomask to asource of activating radiation. The photomask has areas that are opaqueto activating radiation and other areas that are transparent toactivating radiation. Exposure to activating radiation provides aphotoinduced or chemical transformation of the photoresist coating tothereby transfer the pattern of the photomask to the photoresist-coatedsubstrate. Following exposure, the photoresist is developed to provide arelief image that permits selective processing of a substrate.

A photoresist can be either positive-acting or negative-acting. For mostnegative-acting photoresists, those coating layer portions that areexposed to activating radiation polymerize or crosslink in a reactionbetween a photoactive compound and polymerizable reagents of thephotoresist composition. Consequently, the exposed coating portions arerendered less soluble in a developer solution than unexposed portions.For a positive-acting photoresist, exposed portions are rendered moresoluble in a developer solution while areas not exposed remaincomparatively less soluble in the developer solution. Photoresistcompositions are described in Deforest, Photoresist Materials andProcesses, McGraw Hill Book Company, New York, ch. 2, 1975 and byMoreau, Semiconductor Lithography, Principles, Practices and Materials,Plenum Press, New York, ch. 2 and 4.

A major use of photoresists is in semiconductor manufacture where anobject is to convert a highly polished semiconductor slice, such assilicon or gallium arsenide, into a complex matrix of electronconducting paths, preferably of micron or submicron geometry, thatperform circuit functions. Proper photoresist processing is a key toattaining this object. While there is a strong interdependency among thevarious photoresist processing steps, exposure is believed to be one ofthe most important steps in attaining high resolution photoresistimages.

Reflection of activating radiation used to expose a photoresist oftenposes limits on resolution of the image patterned in the photoresistlayer. Reflection of radiation from the substrate/photoresist interfacecan produce spatial variations in the radiation intensity in thephotoresist, resulting in non-uniform photoresist linewidth upondevelopment. Radiation also can scatter from the substrate/photoresistinterface into regions of the photoresist where exposure is nonintended, again resulting in linewidth variations. The amount ofscattering and reflection will typically vary from region to region,resulting in further linewidth non-uniformity. Variations in substratetopography also can give rise to resolution-limiting problems.

One approach used to reduce the problem of reflected radiation has beenthe use of a radiation absorbing layer interposed between the substratesurface and the photoresist coating layer. See for example, PCTApplication WO 90/03598, EPO Application No. 0 639 941 A1 and U.S. Pat.Nos. 4,910,122, 4370,405, 4,362,809, and 5,939,236. Such layers havealso been referred to as antireflective layers or antireflectivecompositions. See also U.S. Pat. Nos. 5,939,236; 5,886,102; 5,851,738;and 5,851,730, all assigned to the Shipley Company, which disclosehighly useful antireflective compositions.

SUMMARY OF THE INVENTION

We have now discovered new antireflective compositions (“ARCs”) for usewith an overcoated photoresist layer.

More specifically, organic coating compositions, particularlyantireflective compositions for use with an overcoated photoresist, areprovided that comprise a resin component that contains ester repeatunits (polyester), such as provided by polymerization of acarboxy-containing compound (such as a carboxylic acid, ester,anhydride, etc.) and a hydroxy-containing compound, preferably acompound having multiple hydroxy groups such as a glycol, e.g. ethyleneglycol or propylene glycol, or glycerol, or other diols, triols,tetraols and the like.

Preferably, an ester functionality is present as a component of, orwithin, the polymer backbone rather than as a pendant or side chainunit. Ester moieties also may be present as a pendant group, butpreferably the polymer also contains an ester functionality along thepolymer backbone. Also preferred is where the ester repeat unitcomprises aromatic substitution, such as optionally substitutedcarbocyclic aryl groups e.g. optionally substituted phenyl, naphthyl oranthracenyl substitution, either as a side chain or more preferablyalong the polymer backbone.

In a further aspect, organic coating compositions, particularlyantireflective compositions for use with an overcoated photoresist, areprovided that comprise a resin component that is obtained frompolymerization of one or more monomers, oligomers or other polymerizedsubunits or materials that comprise hydroxy groups, e.g. 2, 3, or 4hydroxy groups per monomer. Preferably, such hydroxy-containingpolymerizable materials are reacted to form a polyester resin asdiscussed above, particularly by reaction of the hydroxy-containingcarboxy-containing compound (such as a carboxylic acid, ester,anhydride, etc.). Exemplary hydroxy-containing polymerizable materialsinclude diol, triols and tetraols such as a glycol, e.g. ethylene glycolor propylene glycol, or glycerol.

Coating compositions of the invention preferably are crosslinkingcompositions and contain a material that will crosslink or otherwisecure upon e.g. thermal or activating radiation treatment. Typically, thecomposition will contain a crosslinker component, e.g. anamine-containing material such as a melamine or benzoguanamine compoundor resin.

Preferably, crosslinking compositions of the invention can be curedthrough thermal treatment of the composition coating layer. Suitably,the coating composition also contains an acid or more preferably an acidgenerator compound, particularly a thermal acid generator compound, tofacilitate the crosslinking reaction.

For use as an antireflective coating composition, as well as otherapplications such as via-fill, preferably the composition is crosslinkedprior to applying a photoresist composition layer over the compositionlayer.

Antireflective compositions of the invention also preferably contain acomponent that comprises chromophore groups that can absorb undesiredradiation used to expose the overcoated resist layer from reflectingback into the resist layer. Such chromophore groups may be present withother composition components such as the polyester resin or an acidgenerator compound, or the composition may comprise another componentthat may comprise such chromophore units, e.g. a resin separate from thepolyester resin that contains chromophore substitution, or a smallmolecule (e.g. MW less than about 1000 or 500) that contains one or morechromophore moieties, such as one or more optionally substituted phenyl,optionally substituted anthracene or optionally substituted naphthylgroups.

Generally preferred chromophores for inclusion in coating composition ofthe invention particularly those used for antireflective applicationsinclude both single ring and multiple ring aromatic groups such asoptionally substituted phenyl, optionally substituted naphthyl,optionally substituted anthracenyl, optionally substitutedphenanthracenyl, optionally substituted quinolinyl, and the like.Particularly preferred chromophores may vary with the radiation employedto expose an overcoated resist layer. More specifically, for exposure ofan overcoated resist at 248 nm, optionally substituted anthracene andoptionally substituted naphthyl are preferred chromophores of theantireflective composition. For exposure of an overcoated resist at 193nm, optionally substituted phenyl and optionally substituted naphthylare particularly preferred chromophores of the antireflectivecomposition. Preferably, such chromophore groups are linked (e.g.pendant groups) to a resin component of the antireflective composition,such as the polyester resin as discussed above. Particularly preferredchromophore groups are aryl dicarboxylates, particularly naphthyldicarboxylate and phenyl dicarboxylate groups.

Coating compositions of the invention are typically formulated andapplied to a substrate as an organic solvent solution, suitably byspin-coating (i.e. a spin-on composition). In a preferred aspect,compositions of the invention are formulated with a solvent componentthat comprises one or more oxyisobutyric acid esters, particularlymethyl-2-hydroxyisobutyrate. Especially preferred coating compositionsof the invention include a polyester resin, particularly having esterrepeat units as a component of the polymer backbone, and formulated witha solvent component that comprises one or more oxyisobutyric acid esterssuch as methyl-2-hydroxyisobutyrate.

In a further aspect of the invention, antireflective compositions foruse with an overcoated photoresist are provided that have a plurality ofresins selected to provide desired real (n) and imaginary (k) refractiveindex values for the antireflective composition at the exposurewavelength. As is known, the refractive index of an antireflectivecomposition at the exposure wavelength is the complex number N=nik,where n is the real part of N, and is equivalent to what is commonlycalled “the refractive index”, k is the imaginary part of N and isrelated to the absorption coefficient as a function of the exposurewavelength.

More particularly, in this aspect of the invention, an antireflectivecomposition of the invention is formulated with a plurality of resins,at least one of the resins preferably being a polyester resin and/orbeing formed from a multi-hydroxy material, to provide targeted real andimaginary refractive index values. A preferred blend partner is anacrylate resin such as the anthracene acrylate polymers (particularlypolymers that contain polymerized repeat units of hydroxyethylmethacrylate or hydroxyethyl acrylate and methylanthracene methacrylateor other anthracene acrylate) such as disclosed in U.S. Pat. No.5,886,102 assigned to the Shipley Company.

Preferred methods including attaining a desired target real index n frombetween about 1.5 (particularly 1.50) to about 2.1 (particularly 2.10)and a desired imaginary index k from about 0.2 (particularly 0.20) to0.7 (particularly 0.70) by admixing (blending) a polyester resin and anacrylate resin in an antireflective composition of the invention.Preferably, the polyester resin comprises naphthalene groups and thepolyacrylate resin comprises anthracene groups or other chromophoremoieties such as phenyl.

A variety of photoresists may be used in combination (i.e. overcoated)with a coating composition of the invention. Preferred photoresists foruse with the antireflective compositions of the invention arechemically-amplified resists, especially positive-acting photoresiststhat contain one or more photoacid generator compounds and a resincomponent that contains units that undergo a deblocking or cleavagereaction in the presence of photogenerated acid, such asphotoacid-labile ester, acetal, ketal or ether units. Negative-actingphotoresists also can be employed with coating compositions of theinvention, such as resists that crosslink (i.e. cure or harden) uponexposure to activating radiation. Preferred photoresists for use with acoating composition of the invention may be imaged with relativelyshort-wavelength radiation, e.g. radiation having a wavelength of lessthan 300 nm or less than 260 nm such as about 248 nm, or radiationhaving a wavelength of less than about 200 nm or less than about 170 nm,such as about 193 nm or 157 nm.

The invention further provides methods for forming a photoresist reliefimage and novel articles of manufacture comprising substrates (such as amicroelectronic wafer substrate) coated with an antireflectivecomposition of the invention alone or in combination with a photoresistcomposition.

Other aspects of the invention are disclosed infra.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a SEM of a developed photoresist relief image over anantireflective composition having a polyester resin, of Example 34 whichfollows.

FIG. 2 shows a SEM of a developed photoresist relief image over anantireflective composition having a polyester resin, of Example 35 whichfollows.

FIG. 3 shows a SEM of a developed photoresist relief image over anantireflective composition having a polyester resin, of Example 36 whichfollows.

FIG. 4 shows SEMs of developed photoresist relief images overantireflective compositions having a polyester resin, of Example 45(three different resists of Example 45a, 45b and 45c) which follows.

FIG. 5 shows 1:1 lines and spaces (140 nm masking linearity) produced inExamples 50 through 54 which follow.

DETAILED DESCRIPTION OF THE INVENTION

We now provide new organic coating compositions that are particularlyuseful with an overcoated photoresist layer. Preferred coatingcompositions of the invention may be applied by spin-coating (spin-oncompositions) and formulated as a solvent composition. The coatingcompositions of the invention are especially useful as antireflectivecompositions for an overcoated photoresist and/or as planarizing orvia-fill compositions for an overcoated photoresist composition coatinglayer.

As discussed above, organic coating compositions are provided thatcontain ester repeat units. The ester groups are not photoacid-labile,i.e. the ester repeat units do not undergo deblocking or other cleavageduring typical lithographic processing of pre-exposure bake, exposure toactivating radiation, post-exposure heating, and/or development.Preferably, ester repeat units are present in the polymer backbone, i.e.the ester groups (—(C═O)O—) are present on the branched or substantiallylinear chain that forms the polymer length. Also preferred is that suchester groups contain aromatic substitution, e.g. a phenyl, naphthyl oranthracene group, such as may be provided by reaction of a an alkylphthalate with a polyol.

Such a polyester resin may contain other repeat units, either as pendantor side chain units, or as other repeat units along the polymerbackbone. For example, the resin may be a copolymer (e.g. two distinctrepeat units along resin backbone), terpolymer (e.g. three distinctrepeat units along resin backbone), tetraplymer (e.g. four distinctrepeat units along polymer backbone) or pentapolymer (e.g. five distinctrepeat units along polymer backbone). For instance, suitable will bepolymers that contain ether and ester repeat units, or alkylene repeatunits together with ester and ether units. Additional repeat units thatcontain one or more oxygen atoms are preferred for many applications.

Exemplary preferred resins that may be utilized in coating compositionsof the invention include those that are formed by reaction of a compoundthat contains one or more carboxyl (e.g. ester, anhydride, carbocyclicacid) groups together with a compound that contains one or more hydroxygroup preferably at least two hydroxy groups. The carboxyl-containingcompound also preferably may contain two or more carboxyl (—C═OO—)groups. The carboxyl and hydroxy compound are suitably reacted in thepresence of acid, optionally with other compounds if copolymer or otherhigher order polymer is desired, to thereby provide a polyester resin.

Such polyester resins are suitably prepared by charging a reactionvessel with the a polyol, a carboxylate compound, and other compounds tobe incorporated into the formed resin, an acid such as a sulfonic acid,e.g. methane sulfonic acid or para-toluene sulfonic acid, and the like.The reaction mixture is suitably stirred at an elevated temperature,e.g. at least about 80° C., more typically at least about 100° C., 110°C., 120° C., 130° C., 140° C., or 150° C. for a time sufficient forpolymer formation, e.g. at least about 2, 3, 4, 5, 6, 8, 12, 16, 20, 24hours. Exemplary preferred conditions for synthesis of useful resins aredetailed in the examples which follow.

As discussed above, in a further aspect, the invention provides organiccoating compositions, particularly antireflective compositions for usewith an overcoated photoresist, are provided that comprise a resincomponent that is obtained from polymerization of one or more monomers,oligomers or other polymerized subunits or materials that comprisehydroxy groups, e.g. 2, 3, or 4 hydroxy groups per monomer.

Preferably, after reaction of the multi-hydroxy compound to form acomposition reaction, the incorporated unit will have at least one,suitably two or three or more unreacted hydroxy groups. Among otherthings, such hydroxy groups of composition resins can function as sitesfor crosslinking of an antireflective composition that contains theresin.

As discussed above, multi-hydroxy compounds are suitably reacted to forma polyester resin. However, mutli-hydroxy compounds can be incorporatedinto other resins and use din antireflective compositions is accordancewith the invention, such as a polyether, polyurethane or other resin.

Exemplary hydroxy-containing polymerizable materials include diol,triols and tetraols. Suitable hydroxy-containing polymerizable materialsmay include other hetero atoms substitution, particularly nitrogen andsulfur, particularly sulfur as may be present as an alkylthio (sulfide),alkylsulfinyl or alkylsulfonyl moiety. Typical multiplehydroxy-containing materials that can be reacted to form a compositionresin on the invention have at least two carbon atoms, more typically 3,4, 5, 6, 7, 8, 9, or 10 carbon atoms. The polymerizable multiplehydroxy-containing materials may be suitably branched or straight-chaincompounds.

Specifically suitable diols for reaction to form an antireflectivecomposition resin of the invention include e.g. ethylene glycol;1,3-propanediol; 1,2-propanediol; 2,2-dimethyl-1,3-propanediol;2,2-diethyl-1,3-propanediol; 2-ethyl-3-methyl-1,3-propanediol;2-methyl-2-propyl-1,3-propanediol; 2-butyl-2-ethyl-1,3-propanediol;1,4-butanediol; 2-methyl-1,4-butanediol; 1,2-butanediol; 1,3-butanediol;2,3-butanediol; 2,3-dimethyl-2,3-butanediol; 1,5-pentanediol;1,2-pentanediol; 2,4-pentanediol; 2-methyl-2,4-pentanediol;1,6-hexandiol; 2,5-hexanediol; 1,2-hexanediol; 1,5-hexanediol;2-ethyl-1,3-hexanediol; 2,5-dimethyl-2,5-hexanediol; 1,7-heptanediol;1,8-octanediol; 1,2-octanediol; 1,9-nonanediol; 1,10-decanediol;1,2-decanediol; 1,12-dodecanediol; 1,2-dodedanediol;1,2-tetradecanediol; 1,2-hexadecanediol; 1,16-hexadecanediol;1,2-cyclobutanedimethanol; 1,4-cyclohexanedimethanol;1,2-cyclohexanedimethanol; 5-norbonene-2,2-dimethanol;3-cyclohexene-1,1-dimethanol; dicyclohexyl-4,4′-diol;1,2-cyclopentanediol; 1,3-cyclopentanediol; 1,2-cyclooctanediol;1,4-cyclooctanediol; 1,5-cylcooctanediol; 1,2-cyclohexanediol;1,3-cyclohexanediol; 1,4-cyclohexanediol; 1,2-cycloheptanediol;2,2,4,4-tetramethyl-1,3-cyclobutanediol; 1,2-cyclododecanediol;decahydronaphthalene 1,4-diol; decahydronaphthalene-1,5-diol;3-chloro-1,2-propanediol; 1,4-dibromobutane-2,3-diol;2,2,3,3-tetrafluorol,4-butanediol; diethylene glycol; triethyleneglycol; tetraethylene glycol; pentaethylene glycol; dipropylene glycol;isosorbide; isomannide; 1,3-dioxane-5,5-dimethanol;1,4-dioxane-2,3-diol; 1,4-dithiane-2,5-diol; 1,2-dithiane-4,5-diol;2-hydroxyethyldisulfide; 3,6-dithia-1,8-octanediol; 3,3′-thiodipopanol;2,2′-thiodiethanol; 1,3-hydroxyacetone;1,5-dihydroxy-2,2,4,4-tetracholoro-3-pentanone; glyceraldehydes;benzopinacole; 1,1,4,4-tetrphenyl-1,4-butanediol;3,4-bis(p-hydroxyphenol)-3,4-hexanediol; 1,2-benzenedimethanol;1,4-benaenedimethanol; 2,3,5,6-tetramethyl-p-xylene-α,α′-diol;2,4,5,6-tetrachlorobenzene-1,3-dimethanol;2,3,5,6-tetrachlorobenzene-1,4-dimethanol; 2,2-diphenyl-1,3-propanediol;3-(4-chlorophenoxy)-1,2-propanediol; 2,2′-(p-phenylenedioxy)-diethanol;5-nitro-m-xylene-α,α′-diol; 1,8-bis(hydroxymethyl)naphthalene;2,6-bis(hydroxymethyl)-p-cresol; O,O′-bis(2-hydroxyethyl)benzene;1,2-O-isopropylidenexylofuranose; 5,6-Isopropylideneascorbic acid;2,3-O-isopropylidenethreitol; and the like.

Specifically suitable triols for reaction to form an antireflectivecomposition resin of the invention include e.g. glycerol;1,1,1-tris(hydroxymethyl)ethane; 2-hydroxymethyl-1,3-propanediol;2-ethyl-2-(hydroxymethyl)-1,3-propanediol;2-hydroxymethy-2-propyl-1,3-propanediol; 2-hydroxymethy-1,4-butanediol;2-hydroxyethyl-2-methyl-1,4-butanediol;2-hydroxymethyl-2-propyl-1,4-butanediol;2-ethyl-2-hydroxyethyl-1,4-butanediol; 1,2,3-butanetriol;1,2,4-butanetriol; 3-(hydroxymethyl)-3-methyl-1,4-pentanediol;1,2,5-pentanetriol; 1,3,5-pentanetriol; 1,2,3-trihydroxyhexane;1,2,6-trihydroxyhexane; 2,5-dimethyl 1,2,6-hexanetriol;tris(hydroxymethyl)nitromethane; 2-methyl-2-nitro-1,3-propanediol;2-bromo-2-nitro-1,3-propanediol; 1,2,4-cyclopentanetriol;1,2,3-cylcopentanetriol; 1,3,5-cyclohexanetriol;1,3,5-cyclohexanetrimethanol; 1,3,5-tris(2-hydroxyethyl)cyanuric acid;1,2-O-Isopropylideneidofuranose; 1,2-O-isopropylideneglucofuranose;methylxylopyranoside; croconic acid; and the like.

Specifically suitable tetraols for reaction to form an antireflectivecomposition resin of the invention include e.g. 1,2,3,4-butanetetrol;2,2-bis(hydroxymethyl)-1,3-propanediol; 1,2,4,5-pentanetetrol;tetrahydroxy-1,4-benzoquionone; α-methylmannopyranoside;2-deoxygalactose; 3-O-methylglucose; ribose; xylose; and the like.

For antireflective applications, suitably one or more of the compoundsreacted to form the resin comprise a moiety that can function as achromophore to absorb radiation employed to expose an overcoatedphotoresist coating layer. For example, a phthalate compound (e.g. aphthalic acid or dialkyl phthalate (i.e. di-ester such as each esterhaving 1–6 carbon atoms, preferably a di-methyl or ethyl phthalate) maybe polymerized with an aromatic or non-aromatic polyol and optionallyother reactive compounds to provide a polyester particularly useful inan antireflective composition employed with a photoresist imaged atsub-200 nm wavelengths such as 193 nm. Similarly, resins to be used incompositions with an overcoated photoresist imaged at sub-300 nmwavelengths or sub-200 nm wavelengths such as 248 nm or 193 nm, anaphthyl compound may be polymerized, such as a naphthyl compoundcontaining one or two or more carboxyl substituents e.g. dialkylparticularly di-C₁₋₆alkyl naphthalenedicarboxylate. Reactive anthracenecompounds also are preferred, e.g. an anthracene compound having one ormore carboxy or ester groups, such as one or more methyl ester or ethylester groups.

The compound that contains a chromophore unit also may contain one orpreferably two or more hydroxy groups and be reacted with acarboxyl-containing compound. For example, a phenyl compound oranthracene compound having one, two or more hydroxyl groups may bereacted with a carboxyl-containing compound.

Additionally, antireflective compositions may contain a material thatcontains chromophore units that is separate from the polyester resincomponent. For instance, the coating composition may comprise apolymeric or non-polymeric compound that contain phenyl, anthracene,naphthyl, etc. units. It is often preferred, however, that theester-resin contain chromophore moieties.

As mentioned, preferred antireflective coating compositions of theinvention can be crosslinked, e.g. by thermal and/or radiationtreatment. For example, preferred antireflective coating compositions ofthe invention may contain a separate crosslinker component that cancrosslink with one ore more other components of the antireflectivecomposition. Generally preferred crosslinking antireflectivecompositions comprise a separate crosslinker component. Particularlypreferred antireflective compositions of the invention contain asseparate components: a resin, a crosslinker, and a thermal acidgenerator compound. Additionally, crosslinking antireflectivecompositions of the invention preferably can also contain an amine basicadditive to promote elimination of footing or notching of the overcoatedphotoresist layer. Crosslinking antireflective compositions arepreferably crosslinked prior to application of a photoresist layer overthe antireflective coating layer. Thermal-induced crosslinking of theantireflective composition by activation of the thermal acid generatoris generally preferred.

Crosslinking antireflective compositions of the invention preferablycomprise an ionic or substantially neutral thermal acid generator, e.g.an ammonium arenesulfonate salt, for catalyzing or promotingcrosslinking during curing of an antireflective composition coatinglayer. Typically one or more thermal acid generators are present in anantireflective composition in a concentration from about 0.1 to 10percent by weight of the total of the dry components of the composition(all components except solvent carrier), more preferably about 2 percentby weight of the total dry components.

As discussed above, antireflective compositions may suitably containadditional resin component. Suitable resin components may containchromophore units for absorbing radiation used to image an overcoatedresist layer before undesired reflections can occur.

For deep UV applications (i.e. the overcoated resist is imaged with deepUV radiation), a polymer of an antireflective composition preferablywill absorb reflections in the deep UV range (typically from about 100to 300 nm). Thus, the polymer preferably contains units that are deep UVchromophores, i.e. units that absorb deep UV radiation. Highlyconjugated moieties are generally suitable chromophores. Aromaticgroups, particularly polycyclic hydrocarbon or heterocyclic units, aretypically preferred deep UV chromophore, e.g. groups having from two tothree to four fused or separate rings with 3 to 8 members in each ringand zero to three N, O or S atoms per ring. Such chromophores includeoptionally substituted phenanthryl, optionally substituted anthracyl,optionally substituted acridine, optionally substituted naphthyl,optionally substituted quinolinyl and ring-substituted quinolinyls suchas hydroxyquinolinyl groups. Optionally substituted anthracenyl groupsare particularly preferred for 248 nm imaging of an overcoated resist.Preferred antireflective composition resins have pendant anthracenegroups. Preferred resins include those of Formula I as disclosed on page4 of European Published Application 813114A2 of the Shipley Company.

Another preferred resin binder comprises optionally substitutedquinolinyl groups or a quinolinyl derivative that has one or more N, Oor S ring atoms such as a hydroxyquinolinyl. The polymer may containother units such as carboxy and/or alkyl ester units pendant from thepolymer backbone. A particularly preferred antireflective compositionresin in an acrylic containing such units, such as resins of formula IIdisclosed on pages 4–5 of European Published Application 813114A2 of theShipley Company.

For imaging at 193 nm, the antireflective composition preferably maycontain a resin that has phenyl chromophore units. For instance, onesuitable antireflective resin for use with photoresists imaged at 193 nmis a terpolymer consisting of polymerized units of styrene,2-hydroxyethylmethacrylate and methylmethacrylate (30:38:32 mole ratio).Such phenyl group containing resins and use of same in antireflectivecompositions have been disclosed in U.S. application Ser. No.09/153,575, file 1998 and corresponding European Published ApplicationEP87600A1, assigned to the Shipley Company.

As discussed above, particularly preferred chromophore includeoptionally substituted aryl dicarboxylate moieties, particularlyoptionally substituted carbocyclic aryl moieties such as phenyl ornaphthyl dicarboxylate groups such as may be present as a group on aresin (either backbone unit or side chain) or a small molecule (MW lessthan about 1000 or 500) component. It has been found that naphthylenedicarboxylates can be highly effective to absorb undesired reflectionsof exposure radiation of an overcoated photoresist. Such aryldicarboxylate groups may be includes in a coating composition of theinvention by a variety of approaches. For instance, a resin may beemployed (may or may not have ester repeat units that comprises naphthyldicarboxylate units. For instance, an acrylate having a naphthyldicarboxylate group (e.g. one of the carboxylate groups forming theester moiety of the acrylate) may be polymerized with other monomers toprovide a resin with naphthyl dicarboxylate moieties. A naphthylenesubstituted at 2 and 6 positions by carboxylate groups is particularlysuitably, although carboxylate substitution at other naphthyl ringpositions also will be suitable.

Such coating compositions comprising a resin or other component areemployed as described above. Thus, for example, the composition maysuitably comprise a crosslinker and an acid source such as an acid oracid generator compound particularly a thermal acid generator compoundwhereby the applied coating composition can be crosslinked such as bythermal treatment prior to application of an overcoated photoresistlayer.

Preferably resins of antireflective compositions of the invention willhave a weight average molecular weight (Mw) of about 1,000 to about10,000,000 daltons, more typically about 5,000 to about 1,000,000daltons, and a number average molecular weight (Mn) of about 500 toabout 1,000,000 daltons. Molecular weights (either Mw or Mn) of thepolymers of the invention are suitably determined by gel permeationchromatography.

While coating composition resins having absorbing chromophores aregenerally preferred, antireflective compositions of the invention maycomprise other resins either as a co-resin or as the sole resin bindercomponent. For example, phenolics, e.g. poly(vinylphenols) and novolaks,may be employed. Such resins are disclosed in the incorporated EuropeanApplication EP 542008 of the Shipley Company. Other resins describedbelow as photoresist resin binders also could be employed in resinbinder components of antireflective compositions of the invention.

The concentration of such a resin component of the coating compositionsof the invention may vary within relatively broad ranges, and in generalthe resin binder is employed in a concentration of from about 50 to 95weight percent of the total of the dry components of the coatingcomposition, more typically from about 60 to 90 weight percent of thetotal dry components (all components except solvent carrier).

As discussed above, crosslinking-type coating compositions of theinvention also contain a crosslinker component. A variety ofcrosslinkers may be employed, including those antireflective compositioncrosslinkers disclosed in Shipley European Application 542008incorporated herein by reference. For example, suitable antireflectivecomposition crosslinkers include amine-based crosslinkers such asmelamine materials, including melamine resins such as manufactured byAmerican Cyanamid and sold under the tradename of Cymel 300, 301, 303,350, 370, 380, 1116 and 1130. Glycolurils are particularly preferredincluding glycolurils available from American Cyanamid. Benzoquanaminesand urea-based materials also will be suitable including resins such asthe benzoquanamine resins available from American Cyanamid under thename Cymel 1123 and 1125, and urea resins available from AmericanCyanamid under the names of Beetle 60, 65, and 80. In addition to beingcommercially available, such amine-based resins may be prepared. e.g. bythe reaction of acrylamide or methacrylamide copolymers withformaldehyde in an alcohol-containing solution, or alternatively by thecopolymerization of N-alkoxymethyl acrylamide or methacrylamide withother suitable monomers.

Suitable substantially neutral crosslinkers include hydroxy compounds,particularly polyfunctional compounds such as phenyl or other aromaticshaving one or more hydroxy or hydroxy alkyl substitutents such as aC₁₋₈hydroxyalkyl substitutents. Phenol compounds are generally preferredsuch as di-methanolphenol (C₆H₃(CH₂OH)₂)H) and other compounds havingadjacent (within 1–2 ring atoms) hydroxy and hydroxyalkyl substitution,particularly phenyl or other aromatic compounds having one or moremethanol or other hydroxylalkyl ring substituent and at least onehydroxy adjacent such hydroxyalkyl substituent.

It has been found that a substantially neutral crosslinker such as amethoxy methylated glycoluril used in antireflective compositions of theinvention can provide excellent lithographic performance properties.

A crosslinker component of antireflective compositions of the inventionin general is present in an amount of between about 5 and 50 weightpercent of total solids (all components except solvent carrier) of theantireflective composition, more typically in an amount of about 7 to 25weight percent total solids.

Coating compositions of the invention, particularly for reflectioncontrol applications, also may contain additional dye compounds thatabsorb radiation used to expose an overcoated photoresist layer. Otheroptional additives include surface leveling agents, for example, theleveling agent available under the tradename Silwet 7604 from UnionCarbide, or the surfactant FC 171 or FC 431 available from the 3MCompany.

Coating compositions of the invention also may contain one or morephotoacid generator compound typically in addition to another acidsource such as an acid or thermal acid generator compound. In such useof a photoacid generator compound (PAG), the photoacid generator is notused as an acid source for promoting a crosslinking reaction, and thuspreferably the photoacid generator is not substantially activated duringcrosslinking of the coating composition (in the case of a crosslinkingcoating composition). Such use of photoacid generators is disclosed inU.S. Pat. No. 6,261,743 assigned to the Shipley Company. In particular,with respect to coating compositions that are thermally crosslinked, thecoating composition PAG should be substantially stable to the conditionsof the crosslinking reaction so that the PAG can be activated andgenerate acid during subsequent exposure of an overcoated resist layer.Specifically, preferred PAGs do not substantially decompose or otherwisedegrade upon exposure of temperatures of from about 140 or 150 to 190°C. for 5 to 30 or more minutes.

Generally preferred photoacid generators for such use in antireflectivecompositions or other coating of the invention include e.g. onium saltssuch as di(4-tert-butylphenyl)iodonium perfluoroctane sulphonate,halogenated non-ionic photoacid generators such as1,1-bis[p-chlorophenyl]-2,2,2-trichloroethane, and other photoacidgenerators disclosed for use in photoresist compositions. For at leastsome antireflective compositions of the invention, antireflectivecomposition photoacid generators will be preferred that can act assurfactants and congregate near the upper portion of the antireflectivecomposition layer proximate to the antireflective composition/resistcoating layers interface. Thus, for example, such preferred PAGs mayinclude extended aliphatic groups, e.g. substituted or unsubstitutedalkyl or alicyclic groups having 4 or more carbons, preferably 6 to 15or more carbons, or fluorinated groups such as C₁₋₁₅ alkyl orC₂₋₁₅alkenyl having one or preferably two or more fluoro substituents.

To make a liquid coating composition of the invention, the components ofthe coating composition are dissolved in a suitable solvent such as, forexample, one or more oxyisobutyric acid esters particularlymethyl-2-hydroxyisobutyrate as discussed above, ethyl lactate or one ormore of the glycol ethers such as 2-methoxyethyl ether (diglyme),ethylene glycol monomethyl ether, and propylene glycol monomethyl ether;solvents that have both ether and hydroxy moieties such as methoxybutanol, ethoxy butanol, methoxy propanol, and ethoxy propanol; esterssuch as methyl cellosolve acetate, ethyl cellosolve acetate, propyleneglycol monomethyl ether acetate, dipropylene glycol monomethyl etheracetate and other solvents such as dibasic esters, propylene carbonateand gamma-butyro lactone. A preferred solvent for an antireflectivecoating composition of the invention is methyl-2-hydroxyisobutyrate,optionally blended with anisole. The concentration of the dry componentsin the solvent will depend on several factors such as the method ofapplication. In general, the solids content of an antireflectivecomposition varies from about 0.5 to 20 weight percent of the totalweight of the coating composition, preferably the solids content variesfrom about 2 to 10 weight of the coating composition.

A variety of photoresist compositions can be employed with coatingcompositions of the invention, including positive-acting andnegative-acting photoacid-generating compositions. Photoresists usedwith antireflective compositions of the invention typically comprise aresin binder and a photoactive component, typically a photoacidgenerator compound. Preferably the photoresist resin binder hasfunctional groups that impart alkaline aqueous developability to theimaged resist composition.

As discussed above, particularly preferred photoresists for use withantireflective compositions of the invention are chemically-amplifiedresists, particularly positive-acting chemically-amplified resistcompositions, where the photoactivated acid in the resist layer inducesa deprotection-type reaction of one or more composition components tothereby provide solubility differentials between exposed and unexposedregions of the resist coating layer. A number of chemically-amplifiedresist compositions have been described, e.g., in U.S. Pat. Nos.4,968,581; 4,883,740; 4,810,613; 4,491,628 and 5,492,793, al of whichare incorporated herein by reference for their teaching of making andusing chemically amplified positive-acting resists. Coating compositionsof the invention are particularly suitably used with positivechemically-amplified photoresists that have acetal groups that undergodeblocking in the presence of a photoacid. Such acetal-based resistshave been described in e.g. U.S. Pat. Nos. 5,929,176 and 6,090,526.

The antireflective compositions of the invention also may be used withother positive resists, including those that contain resin binders thatcomprise polar functional groups such as hydroxyl or carboxylate and theresin binder is used in a resist composition in an amount sufficient torender the resist developable with an aqueous alkaline solution.Generally preferred resist resin binders are phenolic resins includingphenol aldehyde condensates known in the art as novolak resins, homo andcopolymers or alkenyl phenols and homo and copolymers ofN-hydroxyphenyl-maleimides.

Preferred positive-acting photoresists for use with an underlyingcoating composition of the invention contains an imaging-effectiveamount of photoacid generator compounds and one or more resins that areselected from the group of:

1) a phenolic resin that contains acid-labile groups that can provide achemically amplified positive resist particularly suitable for imagingat 248 nm. Particularly preferred resins of this class include: i)polymers that contain polymerized units of a vinyl phenol and an alkylacrylate, where the polymerized alkyl acrylate units can undergo adeblocking reaction in the presence of photoacid. Exemplary alkylacrylates that can undergo a photoacid-induced deblocking reactioninclude e.g. t-butyl acrylate, t-butyl methacrylate, methyladamantylacrylate, methyl adamantyl methacrylate, and other non-cyclic alkyl andalicyclic acrylates that can undergo a photoacid-induced reaction, suchas polymers in U.S. Pat. Nos. 6,042,997 and 5,492,793, incorporatedherein by reference; ii) polymers that contain polymerized units of avinyl phenol, an optionally substituted vinyl phenyl (e.g. styrene) thatdoes not contain a hydroxy or carboxy ring substituent, and an alkylacrylate such as those deblocking groups described with polymers i)above, such as polymers described in U.S. Pat. No. 6,042,997,incorporated herein by reference; and iii) polymers that contain repeatunits that comprise an acetal or ketal moiety that will react withphotoacid, and optionally aromatic repeat units such as phenyl orphenolic groups; such polymers have been described in U.S. Pat. Nos.5,929,176 and 6,090,526, incorporated herein by reference.

2) a resin that is substantially or completely free of phenyl or otheraromatic groups that can provide a chemically amplified positive resistparticularly suitable for imaging at sub-200 nm wavelengths such as 193nm. Particularly preferred resins of this class include: i) polymersthat contain polymerized units of a non-aromatic cyclic olefin(endocyclic double bond) such as an optionally substituted norbornene,such as polymers described in U.S. Pat. Nos. 5,843,624, and 6,048,664,incorporated herein by reference; ii) polymers that contain alkylacrylate units such as e.g. t-but-yl acrylate, t-butyl methacrylate,methyladamantyl acrylate, methyl adamantyl methacrylate, and othernon-cyclic alkyl and alicyclic acrylates; such polymers have beendescribed in U.S. Pat. No. 6,057,083; European Published ApplicationsEP01008913A1 and EP00930542A1; and U.S. pending patent application Ser.No. 09/143,462, all incorporated herein by reference, and iii) polymersthat contain polymerized anhydride units, particularly polymerizedmaleic anhydride and/or itaconic anhydride units, such as disclosed inEuropean Published Application EP01008913A1 and U.S. Pat. No. 6,048,662,both incorporated herein by reference.

3) a resin that contains repeat units that contain a hetero atom,particularly oxygen and/or sulfur (but other than an anhydride, i.e. theunit does not contain a keto ring atom), and preferable aresubstantially or completely free of any aromatic units. Preferably, theheteroalicyclic unit is fused to the resin backbone, and furtherpreferred is where the resin comprises a fused carbon alicyclic unitsuch as provided by polymerization of a norborene group and/or ananhydride unit such as provided by polymerization of a maleic anhydrideor itaconic anhydride. Such resins are disclosed in PCT/US01/14914 andU.S. application Ser. No. 09/567,634.

4) a resin that contains fluorine substitution (fluoropolymer), e.g. asmay be provided by polymerization of tetrafluoroethylene, a fluorinatedaromatic group such as fluoro-styrene compound, and the like. Examplesof such resins are disclosed e.g. in PCT/US99/21912.

Suitable photoacid generators to employ in a positive or negative actingphotoresist overcoated over a coating composition of the inventioninclude imidosulfonates such as compounds of the following formula:

wherein R is camphor, adamantane, alkyl (e.g. C₁₋₁₂ alkyl) andperfluoroalkyl such as perfluoro(C₁₋₁₂alkyl), particularlyperfluorooctanesulfonate, perfluorononanesulfonate and the like. Aspecifically preferred PAG isN-[(perfluorooctanesulfonyl)oxy]-5-norbornene-2,3-dicarboximide.

Sulfonate compounds are also suitable PAGs for resists overcoated acoating composition of the invention, particularly sulfonate salts. Twosuitable agents for 193 nm and 248 nm imaging are the following PAGS 1and 2:

Such sulfonate compounds can be prepared as disclosed in European PatentApplication 96118111.2 (publication number 0783136), which details thesynthesis of above PAG 1.

Also suitable are the above two iodonium compounds complexed with anionsother than the above-depicted camphorsulfonate groups. In particular,preferred anions include those of the formula RSO₃— where R isadamantane, alkyl (e.g. C₁₋₁₂ alkyl) and perfluoroalkyl such asperfluoro (C₁₋₁₂alkyl), particularly perfluorooctanesulfonate,perfluorobutanesulfonate and the like.

Other known PAGS also may be employed in the resists of the invention.

A preferred optional additive of photoresists overcoated a coatingcomposition of the invention is an added base, particularlytetrabutylammonium hydroxide (TBAH), or tetrabutylammonium lactate,which can enhance resolution of a developed resist relief image. Forresists imaged at 193 nm, a preferred added base is a hindered aminesuch as diazabicyclo undecene or diazabicyclononene. The added base issuitably used in relatively small amounts, e.g. about 0.03 to 5 percentby weight relative to the total solids.

Preferred negative-acting resist compositions for use with an overcoatedcoating composition of the invention comprise a mixture of materialsthat will cure, crosslink or harden upon exposure to acid, and aphotoacid generator.

Particularly preferred negative-acting resist compositions comprise aresin binder such as a phenolic resin, a crosslinker component and aphotoactive component of the invention. Such compositions and the usethereof have been disclosed in European Patent Applications 0164248 and0232972 and in U.S. Pat. No. 5,128,232 to Thackeray et al. Preferredphenolic resins for use as the resin binder component include novolaksand poly(vinylphenol)s such as those discussed above. Preferredcrosslinkers include amine-based materials, including melamine,glycolurils, benzoguanamine-based materials and urea-based materials.Melamine-formaldehyde resins are generally most preferred. Suchcrosslinkers are commercially available, e.g. the melamine resins soldby American Cyanamid under the trade names Cymel 300, 301 and 303.Glycoluril resins are sold by American Cyanamid under trade names Cymel1170, 1171, 1172, Powderlink 1174, urea-based resins are sold under thetradenames of Beetle 60, 65 and 80, and benzoguanamine resins are soldunder the trade names of Cymel 1123 and 1125.

Suitable photoacid generator compounds of resists used withantireflective compositions of the invention include the onium salts,such as those disclosed in U.S. Pat. Nos. 4,442,197, 4,603,10, and4,624,912, each incorporated herein by reference; and non-ionic organicphotoactive compounds such as the halogenated photoactive compounds asin U.S. Pat. No. 5,128,232 to Thackeray et al. and sulfonate photoacidgenerators including sulfonated esters and sulfonlyoxy ketones. See J.of Photopolymer Science and Technology, 4(3):337–340 (1991), fordisclosure of suitable sulfonate PAGS, including benzoin tosylate,t-butylphenyl alpha-(p-toluenesulfonyloxy)-acetate and t-butylalpha(p-toluenesulfonyloxy)-acetate. Preferred sulfonate PAGs are alsodisclosed in U.S. Pat. No. 5,344,742 to Sinta et al. The abovecamphorsulfoanate PAGs 1 and 2 are also preferred photoacid generatorsfor resist compositions used with the antireflective compositions of theinvention, particularly chemically-amplified resists of the invention.

Photoresists for use with an antireflective composition of the inventionalso may contain other materials. For example, other optional additivesinclude actinic and contrast dyes, anti-striation agents, plasticizers,speed enhancers, etc. Such optional additives typically will be presentin minor concentration in a photoresist composition except for fillersand dyes which may be present in relatively large concentrations suchas, e.g., in amounts of from about 5 to 50 percent by weight of thetotal weight of a resist's dry components.

Various substituents and materials (including resins, small moleculecompounds, acid generators, etc.) as being “optionally substituted” maybe suitably substituted at one or more available positions by e.g.halogen (F, Cl, Br, I); nitro; hydroxy; amino; alkyl such as C₁₋₈ alkyl;alkenyl such as C₂₋₈ alkenyl; alkylamino such as C₁₋₈ alkylamino;carbocyclic aryl such as phenyl, naphthyl, anthracenyl, etc; and thelike.

In use, a coating composition of the invention is applied as a coatinglayer to a substrate by any of a variety of methods such as spincoating. The coating composition in general is applied on a substratewith a dried layer thickness of between about 0.02 and 0.5 μm,preferably a dried layer thickness of between about 0.04 and 0.20 μm.The substrate is suitably any substrate used in processes involvingphotoresists. For example, the substrate can be silicon, silicon dioxideor aluminum-aluminum oxide microelectronic wafers. Gallium arsenide,silicon carbide, ceramic, quartz or copper substrates may also beemployed. Substrates for liquid crystal display or other flat paneldisplay applications are also suitably employed, for example glasssubstrates, indium tin oxide coated substrates and the like. Substratesfor optical and optical-electronic devices (e.g. waveguides) also can beemployed.

Preferably the applied coating layer is cured before a photoresistcomposition is applied over the antireflective composition. Cureconditions will vary with the components of the antireflectivecomposition. Particularly the cure temperature will depend on thespecific acid or acid (thermal) generator that is employed in thecoating composition. Typical cure conditions are from about 80° C. to225° C. for about 0.5 to 40 minutes. Cure conditions preferably renderthe coating composition coating layer substantially insoluble to thephotoresist solvent as well as an alkaline aqueous developer solution.

After such curing, a photoresist is applied over the surface of thecoating composition. As with application of the bottom coatingcomposition, the overcoated photoresist can be applied by any standardmeans such as by spinning, dipping, meniscus or roller coating.Following application, the photoresist coating layer is typically driedby heating to remove solvent preferably until the resist layer is tackfree. Optimally, essentially no intermixing of the bottom compositionlayer and overcoated photoresist layer should occur.

The resist layer is then imaged with activating radiation through a maskin a conventional manner. The exposure energy is sufficient toeffectively activate the photoactive component of the resist system toproduce a patterned image in the resist coating layer. Typically, theexposure energy ranges from about 3 to 300 mJ/cm² and depending in partupon the exposure tool and the particular resist and resist processingthat is employed. The exposed resist layer may be subjected to apost-exposure bake if desired to create or enhance solubilitydifferences between exposed and unexposed regions of a coating layer.For example, negative acid-hardening photoresists typically requirepost-exposure heating to induce the acid-promoted crosslinking reaction,and many chemically amplified positive-acting resists requirepost-exposure heating to induce an acid-promoted deprotection reaction.Typically post-exposure bake conditions include temperatures of about50° C. or greater, more specifically a temperature in the range of fromabout 50° C. to about 160° C.

The exposed resist coating layer is then developed, preferably with anaqueous based developer such as an alkali exemplified by tetra butylammonium hydroxide, sodium hydroxide, potassium hydroxide, sodiumcarbonate, sodium bicarbonate, sodium silicate, sodium metasilicate,aqueous ammonia or the like. Alternatively, organic developers can beused. In general, development is in accordance with art recognizedprocedures. Following development, a final bake of an acid-hardeningphotoresist is often employed at temperatures of from about 100° C. toabout 150° C. for several minutes to further cure the developed exposedcoating layer areas.

The developed substrate may then be selectively processed on thosesubstrate areas bared of photoresist, for example, chemically etching orplating substrate areas bared of photoresist in accordance withprocedures well known in the art. Suitable etchants include ahydrofluoric acid etching solution and a plasma gas etch such as anoxygen plasma etch. A plasma gas etch removes the antireflective coatinglayer.

The following non-limiting examples are illustrative of the invention.All documents mentioned herein are incorporated herein by reference.

EXAMPLES 1–24 Resin Syntheses

In each of the following Examples 1 through 16, all reagents wereinitially charged into the reactor with little regard to the order ofaddition. The reaction setup consisted of either a 100-mL (Examples 1–3,7, 8, 10, 12–16 and 20–24) or a 250-mL (Examples 4–6, 9, 11, 17–19)three-neck, round-bottom flask fitted with a mechanical stirrer,temperature control box, temperature probe, heating mantle, condenser,Dean-Stark trap, and nitrogen purge inlet (sweep). Each of the reactionswas heated to the time and temperature indicated in Table 1 below. GPCwas performed on all polymer samples and solutions as indicated in Table1 below. All solid polymers were collected by filtration in a Buchnerfunnel, air-dried, and then dried in vacuo between 40–70° C. For one-potpreparation, the molten polymers were dissolved in solvents favorable toformulation. The percent solutions were based on the theoretical yield.

Example 1 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl nitroterephthalate (12.48 g, 52.17 mmol), dimethyl1,4-cyclohexanedicarboxylate (4.91 g, 24.5 mmol), dimethyl phthalate(2.34 g, 12.0 mmol), dimethyl isophthalate (2.34 g, 12.0 mmol),isosorbide (5.86 g, 40.1 mmol), glycerol (2.81 g, 30.5 mmol),p-toluenesulfonic acid monohydrate (PTSA) (0.26 g, 1.4 mmol) and toluene(20 mL). The resultant polymer was dissolved in tetrahydrofuran (THF),and precipitated in mixture of t-butylmethyl ether (MTBE) and hexanes toobtain 11.6 g (42%).

Example 2 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl isophthalate (18.52 g, 95.37 mmol), dimethyl phthalate(2.33 g, 12.0 mmol), 1,3,5-tris(2-hydroxyethyl)cyanuric acid (15.63 g,59.39 mmol), glycerol (4.80 g, 52.1 mmol), and PTSA (0.54 g, 2.8 mmol).The resultant polymer was dissolved in THF. The polymer could beprecipitated from water, isopropanol (IPA), or MTBE. Collectively, 26 g(70%) of polymer was obtained.

Example 3 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl nitroterephthalate (18.26 g, 76.34 mmol), dimethylisophthalate (2.33 g, 12.0 mmol), dimethyl phthalate (2.33 g, 12.0mmol), 1,3,5-tris(2-hydroxyethyl)cyanuric acid (15.91 g, 60.91 mmol),glycerol (5.58 g, 60.6 mmol), and PTSA (0.55 g, 2.9 mmol). The resultantpolymer was dissolved in THF, and precipitated in MTBE to obtain 26 g(69%).

Example 4 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl nitroterephthalate (45.5 g, 190 mmol), dimethylisophthalate (5.8 g, 30 mmol), dimethyl phthalate (5.8 g, 30 mmol),1,3,5-tris(2-hydroxylethyl)cyanuric acid (39.2 g, 150 mmol), glycerol(14.3 g, 155 mmol), and PTSA (1.1 g, 5.8 mmol). The resultant polymerwas dissolved in enough methyl 2-hydroxyisobutyrate (HBM) to prepare a9.5% solution.

Example 5 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl nitroterephthalate (58.7 g, 245 mmol), glycerol (27.1g, 294 mmol), and para-toluene sulfonic acid monohydrate (PTSA) (0.57 g,3.0 mmol). Enough methyl 2-hydroxyisobutyrate (HBM) was added to preparean 11% solution.

Example 6 Polymer Particularly Suitable for 193 nm ARC and 248 nm ARC

Charge: dimethyl terephthalate (48.5 g, 250 mmol), ethylene glycol (12.4g, 200 mmol), glycerol (9.0 g, 100 mmol), and PTSA (0.54 g, 2.8 mmol).Enough propylene glycol methyl ether acetate (PMA) was added to preparean 8% solution.

Example 7 Polymer Particularly Suitable for 248 nm ARC

Charge: dimethyl 2,6-naphthalenedicarboxylate (24.33 g, 99.63 mmol),dimethylterephthalate (19.44 g, 100.1 mmol), ethylene glycol (7.63 g,123 mmol), glycerol (7.29 g, 79.2 mmol), and PTSA (0.46 g, 2.4 mmol).The resultant polymer was dissolved in a solvent mixture of HBM,anisole, and methyl 2-methoxyisobutyrate (MBM) to prepare a 10%solution.

Example 8 Polymer Particularly Suitable for 248 nm ARC

Charge: dimethyl 2,6-naphthalenedicarboxylate (30.5 g, 125 mmol),dimethylterephthalate (14.5 g, 74.7 mmol), ethylene glycol (7.20 g, 116mmol), glycerol (7.30 g, 79.3 mmol) and PTSA (0.47 g, 2.5 mmol). Theresultant polymer was dissolved in a mixture of anisole andtetrahydrofurfuryl alcohol to prepare a 10% solution.

Example 9 Polymer Particularly Suitable for 248 ARC

Charge: dimethyl 2,6-naphthalenedicarboxylate (47.70 g, 195.3 mmol),dimethyl terephthalate (25.90 g, 133.4 mmol), glycerol (32.90 g, 357.2mmol), PTSA (0.84 g, 4.4 mmol), and anisole (36 g). The resultantpolymer was dissolved in a mixture of methyl-2-hydroxyisobutyrate (HBM)and anisole to prepare 10% solution.

Example 10 Polymer Particularly Suitable for 248 nm ARC

Charge: dimethyl 2,6-naphthalenedicarboxylate (25.61 g, 104.8 mmol),dimethyl terephtalate (13.58 g, 69.93 mmol), glycerol (16.72 g, 181.5mmol), PTSA (0.45 g, 2.4 mmol), and anisole (18.8 g). The resultantpolymer was dissolve in THF and precipitated in IPA to obtain 36.9 g(83%).

Example 11 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl nitroterephthalate (31.78 g, 132.9 mmol), dimethylisophthalate (4.09 g, 21.1 mmol), and dimethyl phthalate (4.10 g, 21.1mmol), 1,3,5-tris (2-hydroxyethyl)cyanuric acid (27.42 g, 105.0 mmol),gylcerol (9.65 g, 105 mmol), PTSA (0.65 g, 3.4 mmol), and anisole (25g). The resultant polymer was dissolved in THF and precipitated in MTBEto obtain 47.2 g (72%).

Example 12 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl nitroterephthalate (16.7 g, 70.0 mmol), dimethylterephthalate (34.9 g, 180 mmol), ethylene glycol (7.80 g, 126 mmol),glycerol (13.8 g, 150 mmol), PTSA (0.28 g, 1.5 mmol), and anisole (8 g).The resultant polymer was dissolved in enough HBM to prepare a 10%solution.

Example 13 Polymer Particularly Suitable for 248 nm ARC

Charge: dimethyl naphthalenedicarboxylate (16.82 g, 68.88 mmol),dimethyl terephthalate (8.91 g, 45.9 mmol), glycerol (10.99 g, 119mmol), PTSA (0.44 g, 2.3 mmol), and anisole (37 g). The resultantpolymer was dissolved in a solvent mixture of HBM and anisole to preparea 6.5% solution. The residual monomer content was filtered out ofsolution by passing through a Buchner funnel.

Example 14 Polymer Particularly Suitable for 248 nm ARC

Charge: dimethyl naphthalenedicarboxylate (30.48 g, 124.8 mmol),glycerol (11.96 g, 12.9.9 mmol), PTSA (0.69 g, 3.6 mmol), and anisole(43 g). The resultant polymer was dissolved in a solvent mixture ofpropylene glycol methyl ether alcohol (PM) and anisole to prepare an18.4% solution.

Example 15 Polymer Particularly Suitable for 248 nm ARC

Charge: dimethyl naphthalenedicarboxylate (32.46 g, 132.9 mmol),dimethyl isophthalate (3.20 g, 16.5 mmol), dimethyl phthalate (3.25 g,16.7 mmol), glycerol (15.96 g, 173.3 mmol), PTSA (0.44 g, 2.3 mmol), andanisole (38 g). The resultant polymer was dissolved in a solvent mixtureof PM and anisole to prepare a 21.1% solution.

Example 16 Polymer Particularly Suitable for 248 nm ARC

Charge: dimethyl naphthalenedicarboxylate (25.59 g, 104.7 mmol),dimethyl terephthalate (13.57 g, 69.88 mmol), glycerol (15.32 g, 166.3mmol), dodecylbenzenesulfonic acid (DDBSA) (0.91 g, 2.8 mmol), andanisole (19 g). The resultant polymer was dissolved in a mixture of PMand anisole to prepare a 22.3% solution.

Example 17 Polymer Particularly Suitable for 248 nm ARC

Charge: 2,6-Naphthalenedicarboxylate (61.1 g, 250 mmol),tris(hydroxymethyl)ethane (30.0 g, 250 mmol), PTSA (10.2 g, 53.6 mmol),and anisole (68 g). The resultant polymer was diluted to 25% solutionwith HBM and precipitated in IPA to obtain 64.1 g (85%).

Example 18 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl terephthalate (31.15 g, 16.04 mmol),1,3,5-tris(2-hydroxyethyl)cyanuric acid (46.09 g, 17.64 mmol), PTSA(1.35 g, 0.710 mmol), and anisole (52 g). The resultant polymer wasdiluted to 25% solution with HBM and precipitated in IPA to obtain 45.3g (67%).

Example 19 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl nitroterephthalate (63.53 g, 265.6 mmol), dimethylisophthalate (8.15 g, 42.0 mmol), dimethyl phthalate (8.27 g, 42.6mmol), 1,3,5-tris (2-hydroxyethyl)cyanuric acid (54.90 g, 210.2 mmol),gylcerol (19.32 g, 209.8 mmol), and PTSA (1.31 g, 6.89 mmol). Theresultant polymer was dissolved in THF and precipitated in MTBE toobtain 97.5 g (74%).

Example 20 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl nitroterephthalate (27.23 g, 113.8 mmol), dimethylisophthalate (3.65 g, 18.8 mmol), dimethyl phthalate (3.37 g, 17.4mmol), 1,3,5-tris (2-hydroxyethyl)cyanuric acid (43.12 g, 165.1 mmol),and PTSA (0.68 g, 3.6 mmol). The resultant polymer was dissolved in THFand precipitated in MTBE to obtain 62.6 g (92%).

Example 21 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl nitroterephthalate (35.80 g, 149.7 mmol), 1,3,5-tris(2-hydroxyethyl)cyanuric acid (43.07 g, 164.9 mmol), and PTSA (0.69 g,3.6 mmol). The resultant polymer was dissolved in THF and precipitatedin IPA to obtain 53.2 g (77%).

Example 22 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl nitroterephthalate (11.08 g, 46.32 mmol), dimethyl5-nitroisophthalate (24.73 g, 103.4 mmol), 1,3,5-tris(2-hydroxyethyl)cyanuric acid (43.06 g, 164.9 mmol), and PTSA (0.69 g,3.6 mmol). The resultant polymer was dissolved in THF and precipitatedin IPA to obtain 53.4 g (77%).

Example 23 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl terephthalate (31.11 g, 160.2 mmol), 1,3,5-tris(2-hydroxyethyl)cyanuric acid (45.80 g, 175.3 mmol), and PTSA (0.67 g,3.5 mmol). The resultant polymer was dissolved in THF and precipitatedin MTBE to obtain 50.0 g (75%).

Example 24 Polymer Particularly Suitable for 193 nm ARC

Charge: dimethyl phthalate (30.91 g, 159.2 mmol), 1,3,5-tris(2-hydroxyethyl)cyanuric acid (46.06 g, 176.3 mmol), and PTSA (0.67 g,3.5 mmol). The resultant polymer was dissolved in THF and precipitatedin MTBE to obtain 51.1 g (76%).

TABLE 1 Reaction Conditions and Results for Synthetic Examples. Rxn TempRxn Time Example (° C.) (hours) Mw (RI) Mn (RI) PDI 1 170–200 14 24751517 1.63 2 160 12 7921 2709 2.92 3 150 12 4552 2066 2.20 4 140–145 201715 1021 1.68 5 134–142 48 1475 1079 1.37 6 145–150 15 5205 1909 2.73 7150–200 4 4065 1782 2.28 8 160 15 8638 2318 3.72 9 150–160 5.5 1225 4252.88 (UV) (UV) 10 150–160 13 16,459 3902 4.22 11 145–155 14 29,067 37857.68 12 140–150 23 2066 1137 1.82 13 150 18 2321 1298 1.78 14 150 2411,025 2243 4.91 15 150 12 5424 1913 2.83 16 150 15.5 5464 2010 2.71 17150 3.3 5958 2703 2.20 18 150 7 4355 2201 1.97 19 150 12 2772 1656 1.6720 150 7.25 4118 2033 2.03 21 150 7.25 2745 1633 1.68 22 150 3 2472 15611.58 23 150 2 3562 2056 1.73 24 150 8 2849 1772 1.61

Examples 25–41 Polymer Evaluations

Polymers of the above Examples were further characterized for eitheroptical density (OD) (Table 2 below), solvent resistance (Table 3below), oxide etch-rate (Table 4 below), or optical parameters (Table 5below). Examples 25–41 illustrate the unique formulation as they relateto the test(s) performed.

Each of the formulated samples was prepared by charging the indicatedcomponents into a clean bottle without regard to order of charge. Thesamples were shaken or placed on rollers until completely dissolved.Each sample was then passed through a 0.2 μm PTFE membrane filter into aclean bottle.

For all wafers (silicon or quartz) spin-coated with the formulatedsamples, the spin time was 30 seconds, and the spin-speeds varied asindicated in the corresponding tables. Then the wafers were baked on ahotplate for 60 seconds at the temperature indicated in the table. Thethickness of the films on silicon wafers was measured by ellipsometry.

General Procedures for OD Determination

For OD measurements, the formulated samples were coated onto bothsilicon and quartz wafers. The thickness of the films on silicon wasmeasured. The absorptivity of the films on quartz was determined by UVspectrophotometry. The absorptivity was measured against a blank quartzwafer. From the thickness and absorptivity measurements, the OD wascalculated at the corresponding wavelengths indicated in Table 2.

General Procedures for Measuring Solvent Resistance

Each sample solution tested for solvent resistance was spin-coated ontoa silicon wafer. The thickness of the wafer was measured usingellipsometry. Ethyl lactate (EL), a solvent commonly used in thephotoresist art, was then poured over the surface of the wafer andallowed to sit for 60 seconds. The wafer was then spun dry at 4000 rpmfor 60 seconds. The thickness was measured again and the difference isreported in Table 3 below.

General Procedures for Measuring Etch-Rate

Each sample solution tested for etch was spin-coated onto two siliconwafers, and the films were measured for thickness. The films were thensubject to oxide etch (Honeywell) for 30 seconds. The thickness of theetched films was then measured, and differences were averaged tocalculate the rates reported in Table 4.

General Procedures for Measuring Optical Parameters

Each sample solution tested for optical parameters was spin-coated ontoa silicon wafer. Ellipsometric techniques were applied to determine thereal (n) and imaginary (k) refractive indices. The results are reportedin Table 5.

Example 25

Formulation: polymer from Example 1 (1 g) and PM (19 g). The sample wastested for OD.

Example 26

Formulation: polymer prepared in Example 2 (1.237 g),tetramethoxygyclouril crosslinker (TMG) (0.234 g), plasticizer (0.301g), PTSA (0.0054 g), photoacid generator (0.0090 g), surfactant (0.0126g), and HBM (28.2 g). The sample was tested for etch.

Example 27

Formulation: polymer from Example 2 (0.466 g), HBM (9.57 g), TMG (0.121g), and PTSA (0.0075 g). The sample was tested for solvent resistance,etch, and optical parameters.

Example 28

Formulation: polymer prepared in Example 3 (0.474 g), HBM (9.67 g), TMG(0.137 g), and PTSA (0.0070 g). The sample was tested for solventresistance, etch, and optical parameters.

Example 29

Formulation: polymeric solution prepared in Example 4 (4.28 g), HBM(5.62 g), and TMG (0.10 g). The sample was tested for OD and solventresistance.

Example 30

Formulation: polymeric solution prepared in Example 5 (3.66 g), HBM(6.25 g) TMG (0.10 g). The sample was tested for OD, solvent resistance,and optical parameters.

Example 31

Formulation: polymeric solution prepared in Example 6 (4.62 g), PMA(5.26 g), and TMG (0.12 g). The sample was tested for OD, solventresistance, etch, and optical parameters.

Example 32

Formulation: polymeric solution prepared in Example 5 (4.00 g),polymeric solution prepared in example 6 (4.50 g), HBM (11.32 g), andTMG (0.20 g). The sample was tested for OD, solvent resistance, etch,and optical parameters

Example 33

Formulation: polymeric solution prepared in Example 7 (7.99 g), TMG(0.20 g), HBM (1.8 g), PMA (5.0 g), and anisole (5.0 g). The sample wastested for OD and solvent resistance.

Example 34

Formulation: the polymeric solution prepared in Example 8 (8.02 g), TMG(0.20 g), anisole (8.19 g), and tetrahydrofurfuryl alcohol (3.60 g). Thesample was tested for OD and solvent resistance.

Example 35

Formulation: polymeric solution prepared in Example 9 (4.00 g), HBM(20.90 g), and TMG (0.10 g). The sample was tested for OD and solventresistance.

Example 36

Amberlite IRN-150 (5 g) was added to the polymer solution prepared inExample 9 (200 g). The sample was placed on rollers for 24 h, and theion-exchange resin was removed from solution by filtration. The sample(4.0 g) was used in formulation with HBM (20 g) and TMG (0.10 g). Thesample was tested for solvent resistance.

Example 37

Formulation: polymeric solution prepared in Example 9 (12.00 g), HBM(17.71 g), and TMG (0.30 g). The sample was tested for etch.

Example 38

Formulation: polymer sample prepared in Example 10 (0.400 g), anisole(6.13 g), tetrahydrofurfuryl alcohol (8.09 g), HBM (10.29 g), PTSA (2.5mg), and TMG (0.100 g). The sample was tested for solvent resistance.

Example 39

Formulation: polymeric solution prepared in Example 12 (12.0 g), HBM(7.4 g), TMG (0.6 g), and PTSA (60 mg). The sample was tested for etch.

Example 40

Formulation: polymeric solution prepared in Example 14 (4.8 g), PM (7.0g), anisole (8.0 g), and TMG (0.24 g). The sample was tested for etch.

Example 41

Formulation: polymeric solution prepared in example 16 (4.8 g), PM (12.4g), anisole (2.6 g), and TMG (0.24 g). The sample was tested for solventresistance.

TABLE 2 Optical Density Spin-speed Bake temp Wavelength OD ExamplePolymer (rmp) (C) (nm) (1/μm) 25 1 2400 105 193 9.1 29 4 2400 180 193105 30 5 2400 180 193 9.0 31 6 2400 180 193 14.2 31 6 2400 180 248 6.832 5, 6 3600 180 193 12.5 33 7 3600 180 248 11.1 34 8 3600 180 248 12.535 9 2400 205 248 10.6

TABLE 3 Solvent Resistance Spin-speed Bake temp Thickness Change ExamplePolymer (rpm) (° C.) (Angstroms) 27 2 2400 150 −2 28 3 2400 150 −2 29 42400 180 −2 30 5 2400 180 −9 31 6 2400 180 −4 32 5, 6 2400 180 −2 33 72400 180 −130  34 8 3600 180 No change 35 9 2400 155 −6 36 9 2400 155Strips completely 38 10  2400 180 +1 41 16  2400 150 No change

TABLE 4 Etch-Rate Spin-speed Bake temp Etch-Rate Example Polymer (rpm)(° C.) (Angstrom/min) 26 2 2000 150 970 28 3 2400 150 1172  31 6 2400180 994 32 5, 6 2400 180 1099  37 9 2400 180 888 39 12  2400 185 — 4114  2000 185 —

TABLE 5 Optical Parameters Bake Spin-speed temp Wavelength ExamplePolymer (rpm) (° C.) (nm) n k 27 2 2400 150 193 1.60 0.400 28 3 2400 150193 1.74 0.405 30 5 2400 180 193 1.66 0.321 31 6 2400 180 193 1.64 0.52031 6 2400 180 248 1.79 0.287 32 5, 6 2400 180 193 1.63 0.440

Example 42 ARC Preparation and Lithographic Processing

An ARC composition of the invention was prepared in a 1-pot reactionwith a low-molecular weight polyester containing naphthyl andterephthalyl groups. The ARC also contained a crosslinker component(melamine/benzoguanimine crosslinker).

A 10 weight % solution of a low MW polyester (MW 800) composed ofapproximately 25 mole % 2,6-naphthalenedicarboxylate groups, 25 mole %terephthalate groups, 50% glycerol, and 0.070% p-toluenesulfonic acid ina solvent blend consisting of 70 weight % methyl 2-hydroxyisobutyrateand 30 weight % anisole was prepared by adding these solvents to a warmpolymer melt consisting of 70 weight % polymer, 29.3 weight % anisoleand 0.7% p-toluenesulfonic acid. This 10% polymer solution was then usedto prepare an antireflective composition.

An antireflective composition was prepared by taking 6.986 g the above10% polymer solution, 0.2 g of Cymel 1123, 0.1 g of hexamethoxymelamine, 0.0014 g of R-08 surfactant (DaiNippon Ink Co.) into 13:654 gof 1-methoxy-2-propanol and 29.059 g of methyl 2-hydroxyisobutyrate. Thesolution was then filtered through a 0.1 micron pore size Teflonmembrane into a clean bottle.

The antireflective coating was spin coated on a 150 mm silicon wafer atabout 2000 rpm, and then baked using a proximity hotplate at 200° C.using a Tel Mark 8 wafer coating track machine. The antireflective filmcoating thickness after bake was 34 nm. Next, a ShinEtsu-551 deep-UVphotoresist was spin coated on top of the antireflective film, and bakedat 110° C./60 seconds to give a 410 nm thick film of photoresist. Thephotoresist was then exposed through a target mask using a 248 nm KrFwafer stepper with a 0.60 NA (⅔ annular setting). The resist film wasthen given a 115° C./60 sec post-exposure bake, and then developed usingShipley MF CD-26 developer (2.38% tetramethyl ammonium hydroxide inwater) in a standard 60 second single-puddle process.

Scanning electron microscopy at 60,000 magnification to examine thequality of the resist patterns. Results showed excellent patternfidelity with sharp clean interface between the resist and theantireflective layer. The resist pattern was free of “standing wave”artifacts caused by reflective interference phenomena. That scanningelectron microscopy image (SEM) of the resist pattern over theantireflective coating is shown in FIG. 1 of the drawings. That SEMresults of a 0.18 micron 1:1 line:space pattern using the antireflectivecomposition of this Example 34 as prepared above.

The real and imaginary refractive indices for the antireflective layerof this Example 42 as prepared above applied on a silicon wafer wasmeasured using ellipsometric techniques. The real refractive index,n=1.986 and the imaginary refractive index; k=0.536.

The real and imaginary refractive indices for the antireflectivecomposition of this Example 42 as prepared above were used as inputparameters to calculate the reflectivity at 248 nm for theantireflective stack into a photoresist using the PROLITH 2 simulationpackage (Finle Technology, division of ASML, The Netherlands). Resultsare that the reflectivity is 0.5% when the antireflective film has athickness of 34 nm.

Example 43 ARC Preparation and Lithographic Processing

An ARC of the invention was prepared from a 1-pot preparation. The ARCcontaining a moderate molecular weight polyester containing naphthyl andterephthalyl groups and a crosslinker (a melamine/glycourilcrosslinker).

An antireflective composition was prepared by taking 6.986 g the above10% polymer solution of Example 34 above, 0.2 g oftetramethoxyglycouril, 0.1 g of hexamethoxy melamine, 0.0014 g of R-08surfactant (DaiNippon Ink Co.) into 13.654 g of 1-methoxy-2-propanol and29.059 g of methyl 2-hydroxyisobutyrate.

The antireflective composition was filtered and lithographically testedin the same manner as Example 42 above. Scanning electron microscopy at60,000 magnification to examine the quality of the resist patterns.Results showed excellent pattern fidelity with sharp clean interfacebetween the resist and the antireflective layer. The resist pattern wasfree of “standing wave” artifacts caused by reflective interferencephenomena. That scanning electron microscopy image (SEM) of the resistpattern over the antireflective coating is shown in FIG. 2 of thedrawings. That SEM showed a 0.18 micron 1:1 line:space pattern using theantireflective composition of this Example 43 as prepared above.

The real and imaginary refractive indices for the antireflective layerof this Example 43 as prepared above applied on a silicon wafer wasmeasured using ellipsometric techniques. The real refractive index,n=1.984 and the imaginary refractive index, k=0.502.

The real and imaginary refractive indices for the antireflective ofExample 43 were used as input parameters to calculate the reflectivityat 248 nm for the antireflective stack into a photoresist using thePROLITH 2 simulation package (Finle Technology, division of ASML, TheNetherlands). Results are that the reflectivity is 1.0% when theantireflective film has a thickness of 33 nm:

Example 44 ARC Preparation and Lithographic Processing

An ARC of the invention was prepare din a one-pot procedure by admixinga polyester containing naphthyl and terephthalyl groups with acrosslinker (melamine/benzoguanimine crosslinker).

A polymer related to that of Example 1 above was synthesized, exceptthat the Mw was increased to 3000 by extending the reaction time. A 10weight % solution of the Mw 3000 polyester with 0.070 weight %p-toluenesulfonic acid in a solvent blend of 70 weight % methyl2-hydroxyisobutyrate and 30 weight anisole % was prepared in the samemanner as described in Example 42 above.

It was found this polymer had somewhat different solubility propertiesas the polymer of Example 42, when formulated into an antireflectivecomposition. Accordingly, we found that adjusting the solventcomposition led to a homogenous solution which spun to giveantireflective film which were essentially defect free. Thus, anantireflective composition was prepared by mixing 6.986 g of the 10%polymer solution of Example 3, 0.2 g of tetramethoxyglycouril, 0.1 g ofhexamethoxy melamine, 0.0014 g of R-08 surfactant (DaiNippon Ink Co.)into 22.05 g of 1-methoxy-2-propanol, 4.90 g of anisole and 17.65 g ofmethyl 2-hydroxyisobutyrate.

The antireflective composition was filtered in the same manner describedin Example 42. The antireflective film quality was examined with aKLA8100 “top-down” low-voltage scanning electron microscope inspectiontool. The film was found to be free of optical defects and also defectsobservable by the inspection tool.

This antireflective composition was lithographically tested in the samemanner as Example 42. Scanning electron microscopy at 60,000magnification to examine the quality of the resist patterns. Resultsshowed excellent pattern fidelity with sharp clean interface between theresist and the antireflective layer. The resist pattern was free of“standing wave” artifacts caused by reflective interference phenomena.That scanning electron microscopy image (SEM) of the resist pattern overthe antireflective coating is shown in FIG. 3 of the drawings. That SEMshows of a 0.18 micron 1:1 line:space pattern using the antireflectivecomposition of this Example 44.

The real and imaginary refractive indices for the antireflective layerof Example 44 above applied on a silicon wafer was measured usingellipsometric techniques. The real refractive index, n=1.985 and theimaginary refractive index, k=0.598.

Example 45 ARC Preparation and Lithographic Processing

Preparation and evaluations of ARCs made from blends of a 1-potpolyester containing naphthyl and terephthalyl groups withmelamine/benzoguanimine crosslinker and anthracenyl acrylate polymers.In the case of Example 45d, the ARC was prepared from a polyester ofExample 17 which comprising naphthyl groups and tris(hydroxymethyl)ethanwith a benzoguanimine crosslinker and anthracenyl acrylate polymers.

In this example, a polyester and an acrylate polymer comprisinganthracene were blended in an antireflective composition. Thus, anantireflective composition was prepared by blending the 10 weight %polyester solution of Example 3 with a branched acrylate polymer of Mw160,000 consisting of 23 mole % 9-anthracenyl methylene methacrylate, 29mole % 2-hydroxyethyl methacrylate, 45.6 mol % methyl methacrylate and2.4 mole % diethylene glycol dimethacrylate. Accordingly, antireflectivecompositions were prepared using the polymers described in the abovesentence according to the following table (weights shown in g as drypolymer):

p- 1- toluene methoxy- methyl 2- acrylate Cymel hexamethoxy sulfonic 2-hydroxy Composition polymer polyester 1123 melamine acid anisolepropanol R-08 isobutyrate 45a 0    0.699 0.200 0.100 0.007 4.90 22.050.0014 22.05 45b 0.489 0.210 0.200 0.100 0.007 4.90 22.05 0.0014 22.0545c 0.349 0.349 0.200 0.100 0.007 4.90 22.05 0.0014 22.05

The real and imaginary refractive indices (n & k) for the antireflectivelayer of Example 45 applied on a silicon wafer was measured usingellipsometric techniques. The real and imaginary refractive indices werethen used as input parameters to calculate the reflectivity at 248 nmfor the antireflective stack into a photoresist using the PROLITH 2simulation package (Finle Technology, division of ASML, TheNetherlands), in order to determine the optimal antireflective thicknessto minimize reflectivity. These results are listed in the Table below:

imaginary thickness to minimize Composition real index n index kreflectivity 45a 1.9489 0.5885 33 nm 45b 1.8042 0.5496 39 nm 45c 1.73590.5092 43 nm 45d 1.82 0.59 40 nm

The antireflective coatings 45a through 45c were spin coated on a 200 mmsilicon wafer at about 2000 rpm, and then baked using a proximityhotplate at 200° C. using a Tel Mark 8 wafer coating track machine. Theantireflective film coating thickness after bake was 34 nm. Next, aShinEtsu-402 deep-UV photoresist was spin coated on top of theantireflective film, and baked at 90° C./60 seconds to give a 600 nmthick film of photoresist. The photoresist was then exposed through atarget mask using a 248 nm KrF wafer stepper with a 0.60 NA. The resistfilms were then given a 110° C./60 sec post-exposure bake, and thendeveloped using Shipley MF CD-26 developer (2.38% tetramethyl ammoniumhydroxide in water) in a standard 60 second single-puddle process.

Scanning electron microscope results of 1:1 180 nm L:S patterns on theantireflectives are shown in FIG. 4 of the drawings. Those relief imagesof Examples 45a through 45c all showed excellent pattern fidelity withno evidence of “footing” or undercutting at the resist:antireflectantinterface.

Example 46 ARC Preparation and Lithographic Processing

Preparation and evaluations of ARCs made from polyesters containinghigher amounts of naphthoate groups.

Polymers similar to Example 45 above were synthesized, except that theconcentration of 2,6-naphthalenedicarboxylate groups in the polyesterpolymer was increased. Antireflective compositions were prepared fromthese polymers and tested in the same manner as described in Example 45above. Results are tabulated below:

real imaginary lithographic results of the Example Mw index n index kresist: anti-reflective interface 45a 3000 2.012 0.5946 clean interface,no footing 45b 3000 2.059 0.5749 clean interface, no footing

The results indicate that polymers containing higher concentrations of2,6-naphthalenedicarboxylate will also yield high performanceanti-reflective coatings.

Example 47 ARCs Particularly Suitable for 193 nm

A composition for 193 nm reflection control was prepared using polyesterpolymer. That polyester was prepared from the thermal condensationreaction of dimethylnitroterephathalate, 1,3,5-trishydroxyethylcyanurisacid, dimethylisophthalate, dimethylphthalate and glycerol. Theanti-reflectant composition contained 2.6% polyester polymer GW3488-13,0.75% of tetramethoxyglycouril (Cytec), 0.041% of Nacure 5225 (KingInd.), and 96.6% of methyl-2-hydroxyisobutyrate (Aldrich). Thecomposition was filtered through a 0.2 um filter.

The prepared antireflectant composition was coated on a silicon wafer bymeans of a spin coater and then heated on a hot plate at a temperatureof 215° C. for 60 seconds. A cross-linked organic film with a uniformthickness of 81 nm was obtained. A positive acting 193 nm photoresist(Shipley Company TS 10) was spin-coated on top of the cross-linkedorganic anti-reflectant film; the photoresist film was then heated on ahot plate at a temperature of 120 degrees C. for 60 seconds. Thephotoresist was exposed to patterned 193 nm radiation in a GCA 193 nmstepper with NA=0.60 and partial coherence=0.70. After exposure, thephotoresist was heated on a hotplate at a temperature of 120° C. for 60seconds. The photoresist was then contacted with a 0.26N aqueoussolution of tetramethylammonium hydroxide. After 60 seconds, thetetramethylammonium hydroxide solution was rinsed off the wafer withdistilled, deionized water and the wafer was spun dried. Line and spacepatterns were obtained.

Example 48 ARCs Particularly Suitable for 193 nm

A composition for 193 nm reflection control was prepared using apolyester polymer that was prepared from the thermal condensationreaction of dimethylnitroterephathalate, dimethylterephthalate, ethyleneglycol and glycerol. The anti-reflective composition was prepared byadmixing 3.06 wt % of that polyester polymer, 0.80 wt % oftetramethoxyglycouril (Cytec), 0.14 wt % of p-toluenesulfonic acid(Aldrich), and 96.0 wt % of methyl-2-hydroxyisobutyrate, with those wt.Percent based on total weight of the composition. The composition wasfiltered through a 0.2 um filter.

The anti-reflective composition was coated on a silicon wafer by meansof a spin coater and then heated on a hot plate at a temperature of 215degrees C. for 60 seconds. A cross-linked organic film with a uniformthickness of 82 nm was obtained. A positive acting 193 nm photoresist(Shipley Company TS 10) was spin-coated on top of the cross-linkedorganic anti-reflective film; the photoresist film was then heated on ahot plate at a temperature of 120 degrees C. for 60 seconds. Thephotoresist was exposed to patterned 193 nm radiation in a GCA 193 nmstepper with NA=0.60 and partial coherence=0.70. After exposure, thephotoresist was heated on a hotplate at a temperature of 120 degrees C.for 60 seconds. The photoresist was then contacted with a 0.26N aqueoussolution of tetramethylammonium hydroxide. After 60 seconds, thetetramethylammonium hydroxide solution was rinsed off the wafer withdistilled, deionized water and the wafer was spun dried. Line and spacepatterns were obtained.

Lithography Results:

Wafers patterned with 193 nm radiation were cross-sectioned and examinedby scanning electron microscopy (SEM). Dense line and space patterns andisolated line patterns at 150 nm feature size were evaluated for profiledefects, including “standing waves” (an uneveness in the resistsidewalls caused by reflective light interference modulating thephotoacid concentration following exposure). No standing waves wereobserved on resist features patterned over the anti-reflectantcompositions of Example 45 or Example 46.

AR coating Resist Esize(150 nm 1:1) Result Example 45 TS10 24 mJ/cm2 nostanding waves Example 46 TS10 24 mJ/cm2 no standing waves

Examples 49–54 Anti-Reflective Coating Formulation and Characterization

Anti-reflective coating compositions of the above examples werecharacterized for optical density (OD), optical properties at 193 nm,oxide etch-rate, and lithographic properties (Table 6, FIG. 5).

Samples for testing were formulated by charging the indicated componentsinto a clean bottle. The samples were shaken or placed on rollers untilcompletely dissolved. Each sample was then passed through a 0.2 μm PTFEmembrane filter into a clean bottle. Wafers (silicon or quartz) werespin-coated with the formulated samples using a spin time of 30–60seconds; spin-speeds varied as necessary to obtain film thickness in therange of 40–120 nm. The spin-coated wafers were baked on a hotplate for60 seconds at 215° C. Film thickness (on silicon wafers) was measured byellipsometry.

General Procedure for OD Determination

Samples were spin-coated onto both silicon and quartz wafers. Filmthickness on the silicon wafer was measured as a proxy for filmthickness on the quartz wafer. The absorptivity of the films on quartzwas determined at 193 nm by UV spectrophotometry vs. an uncoated quartzwafer. The OD of the formulation was calculated using film thickness andabsorbtivity measurements (Table 6).

General Procedures for Measuring Optical Parameters

Formulated samples were spin-coated onto silicon wafers. Ellipsometrictechniques were applied to determine the real (n) and imaginary (k)refractive indices at 193 nm (Table 6).

General Procedure for Measuring Etch-Rate

Formulated samples were spin-coated onto silicon wafers. Film thicknesswas measured using ellipsometry. The films were then subject to oxideetch (C₄F₈/O₂/CO/Ar) for 30–60 seconds. The thickness of the etchedfilms was re-measured and the bulk etch rate was calculated (Table 6).

General Procedure for Lithographic Evaluation

The antireflective coatings of examples 50–54 were spin coated on 150 mmsilicon wafers at 2000–3000 rpm, and then baked using a proximityhotplate at 215° C. using a FSI Polaris 2200 wafer coating trackmachine. The antireflective film coating thickness after bake was 80–82nm. Next, a 193 nm photoresist was spin coated on top of theantireflective film, and baked at 120° C./90 seconds to give a 330 nmthick film of photoresist. The photoresist was, then exposed through atarget mask using a 193 nm ArF wafer stepper with a 0.60 numericalaperature and 0.70 partial coherence. The exposed resist film was givena 120° C./60 sec post-exposure bake and then developed using acommercially available developer (2.38% tetramethyl ammonium hydroxidein water) in a standard 60 second single-puddle process.

The quality of the resist patterns was examined by scanning electronmicroscopy (SEM) at 75,000 magnification. The SEM images showed goodpattern fidelity with a clean interface between the resist and theantireflective layer. The resist pattern was free of “standing wave”artifacts caused by reflective interference phenomena. The SEM image ofa 140 nm 1:1 line:space resist pattern over the antireflective coatingof Examples 49–53 are shown in FIG. 5.

The real and imaginary refractive indices for the antireflective coatingcomposition of Example 46 were used as input parameters to calculate thereflectivity at 193 nm for the antireflective stack into a photoresistusing the PROLITH 2 simulation package (Finle Technology, division ofASML, The Netherlands). Results of the simulation indicate that thereflectivity is 0.9% when the anti-reflective film of Example 49 has athickness of 80 nm.

TABLE 6 OD, Optical Parameters, and Oxide Etch Rate of Examples 49–54Oxide Etch rate Example Polymer OD/μm (193 nm) n/k (193 nm)(Angstrom/min) 49 19  9.3 1.60/0.40 1172 50 20 10.6 1.82/0.39 1352 51 2111.4 1.84/0.38 1425 52 22 11.7 1395 53 23 13.8 1.81/0.48 1167 54 24 13.01.79/0.45 1185

The foregoing description of this invention is merely illustrativethereof, and it is understood that variations and modifications can bemade without departing from the spirit or scope of the invention as setforth in the following claims.

1. A coated substrate comprising: an antireflective composition layercomprising a solvent component comprising one or more oxyisobutyric acidesters; and a photoresist layer over time antireflective compositionlayer.
 2. The substrate of claim 1 wherein the solvent componentcomprises methyl-2-hydroxyisobutyrate.
 3. The substrate of claim 1wherein the antireflective composition further comprises a resin.
 4. Thesubstrate of claim 3 wherein the antireflective composition resin is apolyester.
 5. The substrate of claim 1 wherein the antireflectivecomposition comprises an acid or acid generator compound.
 6. Thesubstrate of claim 1 wherein the antireflective composition comprises acrosslinker.
 7. The substrate of claim 1 wherein the photoresistcomprises a resin that is at least substantially free of aromaticgroups.
 8. The substrate of claim 1 wherein the photoresist comprises aphenolic resin.
 9. A method of forming a photoresist relief image,comprising: applying an antireflective composition layer on a substrate,the antireflective composition comprising a solvent component comprisingone or more oxyisobutyric acid esters; and applying a photoresistcomposition layer over the antireflective composition layer; andexposing and developing the photoresist layer to provide a resist reliefimage.
 10. The method of claim 9 wherein the solvent component comprisesmethyl-2-hydroxyisobutyrate.
 11. The method of claim 9 wherein thephotoresist layer is exposed with radiation having a wavelength of lessthan about 200 nm.
 12. The method of claim 9 wherein the photoresistlayer is exposed with radiation having a wavelength of about 193 nm. 13.The method of claim 9 wherein the antireflective composition furthercomprises a resin.
 14. The method of claim 7 wherein the antireflectivecomposition resin is a polyester.
 15. The method of claim 9 wherein theantireflective composition comprises an acid or acid generator compound.16. The method of claim 9 wherein the antireflective compositioncomprises a crosslinker.
 17. The method of claim 9 wherein thephotoresist comprises a resin that is at least substantially free ofaromatic groups.
 18. The method of claim 9 wherein the photoresistcomprises a phenolic resin.
 19. An antireflective coating compositioncomprising: a resin; an acid or acid generator compound; and a solventcomponent comprising one or more oxyisobutyric acid esters.
 20. Thecomposition of claim 19 wherein the solvent component comprisesmethyl-2-hydroxyisobutyrate.
 21. The antireflective composition of claim9 wherein the resin is a polyester.
 22. The antireflective compositionof claim 9 wherein the antireflective composition comprises a thermalacid generator compound.
 23. The antireflective composition of claim 9wherein the antireflective composition comprises a crosslinker.